North Eastern Regional Power Committee

North Eastern Regional Power Committee Agenda For 6 th Protection Coordination Sub-Committee Meeting Time of meeting : 10:00 AM. Date of meeting : 11 th December, 2012 (Tuesday) Venue : Hotel Grand Starline Guwahati. A. C O N F I R M A T I O N O F M I N U T E S CONFIRMATION OF MINUTES OF 5 th MEETING OF PROTECTION SUB- COMMITTEE OF NERPC. The minutes of 5 th meeting of Protection Sub-committee held on 14 th September, 2012 at Guwahati were circulated vide letter No. NERPC/OP/PCC/2012/5627-42 dated 25 th September, 2012. No observations were received from any of the constituents, the minutes of 5 th PCC meeting maybe confirmed. I T E M S F O R D I S C U S S I O N B. FOLLOW UP ACTION B.1. Submission of details of various Protection Scheme: During the 3rd PCC meeting, Member Secretary had requested all constituents of NERPC to submit the protection details of their transmission system so that the protection scheme and relay setting (reach & time etc.) can be standardized for North-Eastern region. He mentioned that so many trippings of lines could be due to improper relay setting or co-ordination problem of relays owned by different agencies and standardization of protection system and relay settings will improve the situation. 1

During 4 th PCC meeting SE (Com), NERPC had informed that CEA (Technical standards for construction of Electrical Plants & Electrical lines) regulations 2010 provides guidelines for protection schemes at different voltage levels for both Generating stations as well as substations. The document can be downloaded from CEA s website i.e. (www.cea.nic.in). Further, he cited that other Region have already completed their protection standardizations process and NE region should also standardize their protection schemes etc. for the benefit of Constituents. The representative of Tripura had informed that tenders were invited to upgrade their protection system, and upgradation work would be completed in few months time. During 5 th PCC meeting, SE(Com) again reiterated that CEA s regulation clearly recommends the various protection schemes to be provided for protection of lines, transformers/reactors, generators, bus bar, the type relays to be used and DC system to be provided at substation. He further emphasized that as per regulation all protections relay should be of numerical type complying IEC 61850 protocol and all Constituents should initiate action accordingly while replacing / procuring new relays for their system. He also mentioned that some formats, with typical example, have been prepared to provide protection details at each substation and requested all constituents of NERPC to submit the protection details of their transmission system including protection schemes & relay settings etc. in the prescribed format, so that the deficiency in protection scheme in operation at various substations can be reviewed. Accordingly the finalization of relay settings and further course of action can be discussed for standardization of protection system for North-Eastern region. The objective can be achieved only through full cooperation of constituents in the region. Member Secretary (IC) emphasized that healthiness of protection system is required for smooth operation of the grid. Constituents may inform the current status on this issue. B.2. Non Operation of Protective Switchgear of DOP, Manipur Undesirable tripping of 132kV Imphal (PG) Imphal (S) Line and 132kV Dimapur Imphal Line during fault in Manipur system due to non-operation of protective switchgear of Manipur system is being observed since long. The issue was discussed in details during 9th TCC & NERPC Meeting held on 11th & 12th August 2010. During the meeting, Manipur had informed that necessary action is being taken to replace old and outdated equipments. During 4 th PCC meting the status could not be updated as Manipur representatives were not present. During 5 th PCC meeting, POWERGRID informed that they have reduced the time delay setting of Zone-3 so that the 132kV Imphal-Imphal line gets tripped before spreading of the fault to other areas. Manipur representative had informed that the renovation of old Sub-stations is being done in phased manner as per CEA guidelines. Presently renovation work of Yerumbum S/S is in process and subsequently two more S/S (Karong and Kackching) will be taken up. Manipur may inform the current status. 2

B.3. Frequent Tripping Of 33kV System of DOP, AP at Nirjuli and Ziro During 9th TCC & NERPC Meeting, the issue was discussed in details and Arunachal Pradesh informed that they have already initiated various measures to reduce no. of faults on 33 KV lines owned by Dept. of Power, Govt. of Arunachal Pradesh. During 10th TCC & NERPC Meeting, POWERGRID again expressed concern for nonreduction of no. of faults in 33kV Feeders. Arunachal Pradesh again assured to take necessary action urgently to reduce no. of faults in their 33kV lines. During 4th PCC Meeting the Sub-committee requested POWERGRID to monitor the status of trappings for one more month and the same would be reviewed again in the next PCC meeting. During 5 th PCC meeting POWERGRID inform that the status of tripping is still at higher side as reflected below: A. 132/33kV Ziro Sub Station Sl. Jan 12 & FEB 12 33 KV feeder No. Nos. Tripping/month 1 Kurung Kamey 32 16 2 Old Ziro 24 12 3 Kimin 62 31 B. 132/33kV Nirjuli Sub Station Sl. Jan 12 to Aug 12 33 KV feeder No. Nos. Tripping/month 1 AP #1 88 11 2 AP #2 124 15.5 3 AP #4 10 1.25 POWERGRID requested Arunachal Pradesh to take necessary action on priority to reduce no. of faults in 33kV feeders owned by DoP, Govt. of Arunachal Pradesh to avoid further failure of transformers at Nirjuli and Ziro Sub Stations. Ar. Pradesh representative stated that the topography of Ar. Pradesh is very difficult because of which maintenance of these lines is getting difficult. Further, POWERGRID informed that there is no improvement in tripping. The present tripping rate during last 2/3 months is as below: No. of trippings during September 12 November 12 are as below: 3

A. 132/33kV Ziro Sub Station Sl. Oct-Nov 12 33 KV feeder No. Nos. Tripping/month 1 Kurung Kamey 16 8 2 Old Ziro 13 6.5 3 Kimin 22 11 B. 132/33kV Nirjuli Sub Station Sl. Sep 12 to Nov 12 33 KV feeder No. Nos. Tripping/month 1 AP #1 20 6.67 2 AP #2 74 24.67 3 AP #4 2 0.67 Arunachal may inform action plan for reduction in trippings. B.4. T- Connection of Lekhi Sub Station During 4 th PCC meeting, POWERGRID had informed that 132kV Ranganadi-Nirjuli Line is being tapped (i.e. operating with T connection) to feed Lekhi Sub Station instead of LILO since Aug/Sept 2008 and had requested Dept. of Power, Ar. Pradesh to expedite the action for LILO of Ranganadi Nirjuli line at Lekhi sub-station. SE, Ar. Pradesh had informed that the LILO arrangement at Lekhi S/S would be completed by January, 2012. However, till date the LILO arrangement has not been completed at Lekhi Sub Station. POWERGRID informed that some corrective action is to be taken otherwise the transformer at Nirjuli substation will again fail. Assam stated that the tapping of line should be stopped as it is not advisable and the LILO should be restored at the earliest in the interest of the Region. Ar. Pradesh representative stated that he will take up the matter to their higher authority to complete the job as early possible. During 5 th PCC meeting, SE(Com.) emphasized that T-connection is not a healthy practice and should normally be avoided as such arrangement leads to unwanted trippings of main line. The committee requested NERPC Secretariat to take up the matter with DoP, Ar. Pradesh to complete the LILO at the earliest. Ar. Pradesh may inform the current status. 4

B.5. Tripping of all Feeders Connected to Khliehriat (PG) Sub Station due to Fault in MeECL System POWERGRID had informed that there were several instances of tripping of all feeders connected to 132kV Khliehriat (PG) Sub Station during fault in MeECL System. From such tripping it was evident that the protective switchgear of MeECL beyond Khliehriat (MeECL) Sub Station had failed to clear fault which had resulted in fault at 132kV Khliehriat (PG) Sub Station. The representative of MeECL had informed that the earlier trippings in Khliehriat was due to PT failure, but the PT & associated cables etc. was replaced in November, 2011 and such trippings should not occur again. During 4 th PCC meeting, the Sub-committee had advised Meghalaya to check their protection schemes, ground clearances etc., before allowing the 132 KV NEHU Khliehriat line to be in closed condition However, POWERGRID informed that again two instances of trippings of Khliehriat- Khliehriat-I feeder, due to fault in MeECL system, has been recorded since January 12. During 5 th PCC meeting, MeECL representatives had informed that Distance Protection Relays along with all other protection schemes are in place in MeECL lines since June, 2012. The committee requested POWERGRID to monitor the Khliehriat-Khliehriat-I feeder. POWERGRID informed that two nos. trippings of Khliehriat-Khliehriat-I (PG) occurred in September 12 due to fault in Khliehriat (MeECL) - NEIGRIHMS feeder. The faults was reflected to POWERGRID S/S because failure of the CB of NEIGRIHMS feeder at Khliehriat (MeECL) due to problem in the protection trip ckt. of the CB. As per information collected from Khliehriat (PG) S/S, the problem rectified by MeECL in Oct-12. Trippings to be observed in furure. PGCIL may give the current status. B.6. Commissioning of Line CVTs of 132kv Khliehriat (PG) - Khliehriat (MeECL) Line # II The CVTs of Khliehriat (MeECL) Bay # II at Khliehriat (PG) Sub Station was erected but not commissioned till date. Presently the voltage input for Distance relay as well as for Back up protection relay is being taken from Bus CVT installed in POWERGRID, Khliehriat Sub-station. Matter was informed to R.E (Me.ECL), Khliehriat for taking necessary action in this connection. During 4 th PCC meeting, the representative of Meghalaya had informed that the matter would be taken up with the concern division to commission the CVTs of Khliehriat at the earliest. During 5 th PCC meeting, MeECL representatives stated that they will take up the matter again with R.E., MEECL and the work will be completed at the earliest. MeECL/POWERGRID may inform the status. 5

B.7. Installation of BMK at Khliehriat (MeECL) Bay # II at Khliehriat (PG) Station CM, POWERGRID had informed that during the commissioning of Khliehriat (MeECL) Bay # II at POWERGRID s Khliehriat Sub Station, MeECL had excavated pit for installation of BMK and the pit was a safety hazard. Matter was referred to R.E (MeECL), Khliehriat for taking necessary action. During 4 th PCC meeting, the representative of Meghalaya had informed that the concern division would be requested to look into the matter. The status quo is still maintained even after 8 months. During 5 th PCC meeting, MeECL representatives stated that they will take up the matter with R.E., MEECL and the work will be completed at the earliest. Me.ECL may inform the current status for installation of BMK. B.8. Non-Functioning of 48V Battery Bank at Samaguri (AEGCL) Sub Station POWERGRID had informed that the 48V Battery Bank at 220/132kV Samaguri Sub Station of AEGCL was defective and the load was being fed directly by the charger. POWERGRID had replaced obsolete PLCC (ETI) and CB (MOCB) and Auto Reclose Scheme was to be put in service. During 4 th PCC meeting, the representative of Assam had informed about the commissioning of the new battery and charger and POWERGRID was to verify the status as reported by Assam. During 5 th PCC meeting, POWERGRID informed that while checking the system, when the charger was switched off, the PLCC went out of service. The connection is required to be rechecked and also it appears that there is earth fault in DC system. Assam informed that there may be some connection error as recently new battery and charger has been replaced because of some problem in old battery system and regarding the earth fault in DC system, they are finding difficulty to locate the fault. The committee requested Assam to recheck the connection and try to resolve the issue at the earliest taking the help of POWERGRID. POWERGRID informed that their personnel visited Samaguri S/S and found that the Battery Bank (feeding the POWERGRID PLCC Panels) was disconnected from the Charger and as a result when the charger was switched off or AC power was not available the PLCC panels went out of service. This was due to problem (in charging) in the new charger. Hence, the load of the PLCC panels was shifted from the new 48V Charger (that was not functioning) to the 48V charger for ULDC to avoid power interruption to the PLCC panels. The PLCC panels are now running with the ULDC charger & battery bank. Assam/POWERGRID may inform the current status. 6

B.9. Installation of 2nd Distance Protection Relay (DPR) for 220KV and above System POWERGRID had already installed 2nd Distance Protection Relay (DPR) for all 220kV and above voltage level lines as per the CEA regulation. The status of installation of 2nd DPR in respect of following lines was still awaited from concerned utility S. No. Station Line Utility Status 1 Kopili HEP 220 KV Misa #1 NEEPCO 2 Kopili HEP 220 KV Misa #II NEEPCO 3 Kopili HEP 220 KV Misa #III NEEPCO 4 Kathalguri PH 220 KV Misa NEEPCO 5 Kathalguri PH 220 KV Mariani NEEPCO 6 Samaguri SS 220 KV Balipara AEGCL 7 BTPS SS 220 KV Salakati # I AEGCL 8 BTPS SS 220 KV Salakati # II AEGCL The representative of NEEPCO had informed that order was placed for procurement of relays in respect of lines at Sl. No. 1 to 5 and the material is was expected to be reach at site by 31.03.2012. Assam also had informed that one Distance Protection Relay on Samaguri side has been installed. As per CEA regulation, where two distance protection has been provided, it is also required to ensure that separate directional earth fault relay is either provided or activated in case of Numerical distance relay to take care of high resistance faults. During 4 th PCC Meeting the Sub-committee recommended to replace obsolete relays with numeric relay for complying with IEC 61850 protocol in phased manner. During 5th PCC meeting, NEEPCO informed that they have completed the installation of the 2nd DPRs on their 220 kv lines as per the CEA guidelines. Assam stated that two of their DPRs are being utilized by POWERGRID in Misa- Samaguri Lines; as soon as they receive their DPRs from POWERGRID it will be installed in BTPS lines. POWERGRID informed that it will take 3-4 months. Above Utilities may intimate the current status. B.10. Installation of Bus Bar Protection in 220kV System On 17-05-12 at 01:43 hrs, the following multiple trippings occurred due to failure of post insulator of R-ph Isolator in Mariani Bay at Samaguri S/S: 1. 220kV Misa-Samaguri # I & II at Samaguri (AEGCL) end tripped on Backup DEF (fault also detected by DPR of these two feeders at Samaguri end in Z3 (reverse)). 2. 220kV Balipara-Samaguri Line tripped on Backup DEF at Samaguri end. 3. 400/220kV ICT tripped at Misa S/S on Directional E/F. 4. Misa-Kathalguri Line tripped at Misa S/S on O/V. 5. Misa-Mariani Line tripped at Misa S/S on O/V. 7

Result: The above trippings led to total voltage loss at Misa S/S & consequently all the connecting lines viz. 220 kv D/C Misa-Kopili, 220 kv D/C Misa-Byrnihat & 220 kv D/C Misa-Dimapur had tripped. Further, power flow to the 132kV pocket through 132 kv Khandong-Kopili-II (36 MW) was interrupted. Also, power flow to Dimapur S/S through the 220 kv Dimapur-Misa lines was also interrupted. Subsequently, the 132kV Dimapur-Imphal & 132kV Jiribam-Loktak-II lines tripped with indication of Power Swing and generation units at RC Nagar Thermal Plant tripped on under-frequency. The above events led to total power interruption. Observation: During the disturbance huge flashover on line Isolator in the 220 kv Mariani bay at Samaguri (AEGCL) S/S was observed. And the post insulator of R-ph Isolator was found totally shattered. The fault was in Bus Bar Zone at Samaguri S/S (AEGCL). As there is no Bus Bar Protection installed in Samaguri S/S, such multiple faults occurred to clear the fault. Further, the indication of E/F relays at Samaguri S/S during the above event shows that the relays operated for fault in the reverse directions. POWERGRID, vide letter no. NESH/OS/1001/91 dtd. 22-05-12, have requested AEGCL to explore the possibility of implementation of Bus Bar Protection scheme and also to check & ensure the healthiness of the Directional Earth Fault relays. During 5 th PCC meeting, the matter was deliberated and SE(Comml) reiterated that for all 220 kv and above voltage class substations, Bus-bar protection and LBB protection are mandatory as per the CEA s Regulations. Moreover, LBB protection is an inbuilt feature of modern numerical relay. Therefore, utilities should go for numerical busbar protection. He also highlighted that the transmission system is expanding with addition of generation, system is becoming more complex and hence importance of busbar protection is also increasing. Even important 132kV substations should have bus bar protection. Assam informed that they are planning for installation of Bus Bar Protection in 220kV substations at Mariani and Samaguri. Assam may inform the current status. B.11. Parallel Operation of 3x60 MVA Transformer with 160 MVA Autotransformer at Kopili Assam had informed that right from the time of the commissioning of 160 MVA Auto transformer of Power Grid at Kopili, the existing 3 numbers of 20 MVA, single phase transformers, supplied by NEEPCO, are not in working condition. The NEEPCO representative had also informed that the above said transformers were not charged since March, 2011. 8

During 77 th OCC meeting NEEPCO informed that the 3x30 MVA Transformers was successfully charged from 220 kv side on 8 th September, 2012. The Committee inquired from NEEPCO about the percentage impedance of both transformers to explore the parallel operation. NEEPCO agreed to provide the information in the next OCC meeting. The Committee agreed and requested POWERGRID to explore for more possibility for utilizing these transformers as these are regional projects and cannot be kept idle. It was also decided that possibility will be explored for charging the ICT along with 132 kv Kopili Khandong ckt-i in the event of shut down of 132 kv Kopili Khandong ckt-ii. During 78 th OCC meeting, NEEPCO submitted the percentage impedance of 3x20 MVA transformers to the committee. The committee requested POWERGRID to check with the existing 160 MVA ICTs percentage impedance and explore the possibility of parallel operation of both the transformer banks. During 79 th OCC meeting, POWERGRID informed that they have compared the percentage impedance of 3x20 MVA transformers with the existing 160 MVA ICT and found it to be within permissible limit. The vector group of the banks is to be checked to explore the possibility of parallel operation of 3x20 MVA transformers with the existing Kopili ICT. The committee requested POWERGRID and NEEPCO to make the necessary arrangement/tests required to check the possibility of parallel operation. B.12. Automatic demand management, SPS & Islanding schemes: As a defense mechanism from possible grid collapse and also to ensure safe & secure operation of grid it is essential to put in place i) Automatic demand management schemes in every state, ii) SPS & iii) Islanding schemes as discussed in 76th OCC meeting. Additional UFRs & df/dt relays may be required for implementation of the schemes. The Sub-committee had decided to discuss further in detail. B.13. SPS scheme for Pallatana It was observed from load flow studies carried out by NERLDC that tripping of Pallatana unit during peak hours would cause loading of Kopili ICT (160 MVA). To save the situation shedding of around 100 MW of load would be required in the 132 KV pocket through SPS. 9

During 76 th OCC meeting, DGM, NERLDC had informed that a special protection scheme is required to be planned for shedding the above load. The committee advised NERPC Secretariat to design the SPS in consultation with NERLDC, Assam, Meghalaya, Tripura, NEEPCO, NHPC and OTPC. POWERGRID representatives had informed that not only SPS but protection schemes are also required to be reviewed before commissioning of Pallatana GBPP. Also from the load flow study it was observed that in certain lines there will be reverse flow of power due to tripping of Pallatana. The committee had requested POWERGRID to study the protection schemes and prepare a report. During 77th OCC meeting, DGM, NERLDC stated that in case of tripping of Pallatana unit, around 120 MW of load shedding through SPS would be required in Mizoram, Tripura and South Assam (each 40 MW) and some load shedding would be required in Meghalaya. POWERGRID informed that the implementation of SPS for tripping of far off lines/loads will be difficult as there will be co-ordination problem because of non-availability of communication links and NERLDC should find some other nearby lines or SPS can be linked with Kopili ICT. NERLDC had informed that some radial lines in NER system have been identified for disconnecting during emergency conditions to save the grid and SPS can be implemented on those lines which are available in 132 kv Pocket. All the constituents agreed for implementation of SPS on these lines and also for emergency disconnection of listed lines in case of necessity. NERLDC was to prepare the SPS scheme in consultation with NERPC & POWERGRID. During 78 th OCC meeting, the committee requested NERLDC to prepare the SPS scheme of Pallatana in consultation with NERPC and POWERGRID. During 79 th OCC meeting, NERLDC informed that lines have been identified in NER system for disconnection during emergency conditions to save the grid. SPS can be planned accordingly. The committee requested NERLDC to give the list of lines associated with tripping of Unit-1 at Pallatana and POWERGRID was requested to plan the implementation of the SPS scheme. NERLDC/POWERGRID may inform the current status B.14. Implementation of islanding scheme in NER For survival of different parts/pockets (with identified generation along with some load) of NER grid in the event of grid disturbance, it has been proposed that islanding schemes may be planned & implemented. During 76 th OCC meeting, DGM, NERLDC stated that some islanding schemes need to be planned so that the islands survive during any grid disturbance so that startup power can be extended to other generating stations. 10

During 77 th OCC meeting, two proposals for islanding scheme were discussed. In both proposals, first step is isolation of NER from NEW Grid at a particular frequency by tripping of 400kV D/C line and 220kV D/C line connecting ER and NER. In one case it has been proposed for formation of two Sustainable Small System (SSS) and then Unit islanding and ultimately Safe shutdown of Generating units when frequency falls to different levels. The frequency level at which actions are to be initiated is to be finalized after discussion. The Committee requested all the constituents to study the islanding schemes and communicate their comments/suggestions at the earliest so that the islanding scheme for NER can be finalized. Further, DGM, NERLDC informed that the list of radial lines in NER system, which can be tripped during emergency to save the grid, have been identified. During emergency there may not be time to co-ordinate with SLDC (like written message etc.) before taking such action. However, formal communication shall be made by NERLDC afterwards. During 79 th OCC meeting, the committee felt that further study is required before finalizing the islanding scheme for NER. The committee requested all the NER constituents to study their systems and give suggestions/comments, if any before finalization of the same. All constituents had agreed. B.15. Ensuring FGMO/RGMO, AVR & PSS tuning for operation of units: In line with IEGC & other regulations, the following aspects are required to be ensured for operation of generating units: i. Operation of generators under Free Governor Mode of Operation (FGMO) or Restricted Governor Mode of Operation(RGMO). ii. Operation of Generating Units within capability limits as per Capability Curves. iii. Proper settings of Automatic Voltage Regulator (AVR) and iv. Proper tuning of Power System Stabilisers (wherever available). During 5 th PCC meeting, committee requested all constituents to intimate the status in next OCC/PCC meeting. All constituents had agreed to ensure above requirements and intimate the status. 11

B.16. Availability and Healthiness of DAS (Data Acquisition System), TSE (Time Synchronising Equipment), DR (Disturbance Recorder) and EL (Event Logger): The availability of DAS, TSE, DR & EL at all the Generating stations and Grid substations (above 132 kv) is of paramount importance. If not available, the same are required to may be provided as per clause no 4.6.3 of IEGC for recording the dynamic performance of the system. These data are to be archived in millisecond interval and have to be furnished to NERLDC whenever required for system study. Committee had requested all constituents to intimate their action plan for putting DAS, TSE, DR & EL in place (if not available). B.17. Non furnishing of data to NERLDC by utilities of NER: NERLDC informed that data pertaining to normal operation as well as those pertaining to major incidence (recent grid incidence, heavy oscillations of Ranganadi & Doyang machines on 26.08.12 from 0215 Hrs to 0245 Hrs) are not being furnished by NEEPCO. The information is required for analysis of the problems. NERLDC had informed that data of Ranganadi HEP was not received. NEEPCO had agreed to furnish the data pertaining to Ranganadi for analysis of problem. NEEPCO may inform the current status. B.18. Z-3 Protection settings in respect of transmission lines: In the aftermath of recent twin major grid disturbances in NEW grid on 30th & 31st July, 2012, the Zone-3 protection settings of different transmission lines (132 kv & above) assumed high importance and loadability of transmission lines based on Zone-3 settings need to be reviewed on urgent basis. In view of above, all constituents were requested to furnish the existing Zone-3 protection settings (at both ends) of 132kV and above voltage class lines. During 5 th PCC meeting, the sub-committee decided that the Z-3 setting should be done properly to differentiate between load encroachment and Z-3 fault. Committee decided to discuss further in detail after getting information from various utilities. 12

C. N E W I T E M S C.1 Independent third party audit of protection system The Chairperson, CEA vide his D.O letter No. 7/AI/GD/GM/2012/397-407, addressed to Hon ble Chairperson, NERPC had requested for completion of independent third party audit of protection system and to ensure operationalisation of Under Frequency Relay (UFR) and df/dt relay based automatic load shedding within one month. In response to above letter NERPC vide letter No. NERPC/OP/OCC/2012/5687-702 had circulated extract of CEA & CERC regulation and some formats, with typical example (which can be downloaded from NERPC website), to help in collecting various information. No. of groups need to be formed to carry out the protection audit. The action plan needs to be discussed so that the work can be completed as early as possible. However, the self-certification (by STUs / CTU) in respect of operationalisation of Under Frequency Relay (UFR) and df/dt relay based automatic load shedding may please be submitted in the prescribed format to NERPC and CEA at the earliest. During 79 th OCC meeting, SE (Comml), NERPC informed that as recommended by Enquiry Committee, the third party independent audit for the Protection systems in NER is to be completed as early as possible and presently Ministry of Power and CEA are also monitoring the progress in various regions it very closely. Therefore, for the benefit of the NER, the upgradation of protection system is very much required for smooth and reliable operation of grid and action should be initiated at the earliest. Further, he informed that third party independent audit of Protection systems for Northern region has already been completed by PGCIL in association with CPRI and other regions have also started their action plan. He informed that in NER there are about 135 Nos. of substations/ generating stations of 132kV and above voltage class and also proposed to carryout protection audit for all these substations / generating stations as 132kV system forms the backbone of NER unlike other regions. Since arrangement of funds is the major constraint in NE region, small groups /teams have to be formed taking representation from NER constituents. The committee decided to form teams comprising of four (4) members from different state utilities/owner, PGCIL/NEEPCO/NHPC and NERPC/NERLDC. NERPC will co-ordinate the audit and prepare the further course of action in consultation with NERLDC and POWERGRID. The nominated member of NERPC/NERLDC will be the co-ordinator of each group. NERPC, in consultation with POWERGRID and NERLDC, had prepared the detailed plan for carrying out the audit of protection system of all 132 kv and above voltage class substations/generating stations in NER (The copy of the same is enclosed at Annexure C.1). All the constituents were requested to nominate their representatives for the audit and the proposed dates were to be finalized during OCC/PCC meeting. NERPC vide letter dated 26 th and 30 th November, 2012 had requested PGCIL and other constituents to provide logistic support inform of road transport and stay at various places in NER. 13

C.2 Protection issues relating to running of Generating Unit-1at Palatana in full capacity for 72 hrs The trial run for Generating Unit-I at Palatana is in progress. PGCIL / NERLDC may inform the committee about any abnormality observed in operation of protection system during trial run of the machine. Further PGCIL may also inform if any special measures / precaution are to be taken by constituents during continuous run of Unit at full / base load for 72 hours, taking into account the available transmission elements in the NER system. C.3 Details of Installations and self-certification (by STUs and CTUs) in respect of operationalisation of Under Frequency Relays (UFRs) in NER systems and additional requirement of UFR and df/dt relays: During 79 rd OCC, Manipur had informed that the UFRs have been installed on 33 kv Yurembum-Limukhong radial feeder as advised by the committee. In the process installation of all UFRs in the NER has been completed as per earlier decision of the committee. Further all constituents (STUs and CTUs) were requested to furnish the relevant information in the format prescribed by CEA. It was also discussed that the requirement of UFR and df/dt relays need to be reviewed based on the recommendation of the enquiry Committee constituted by the Ministry of Power headed by Chairperson CEA. C.4 Major Grid disturbances during the August, 2012 to October, 2012. There was no major grid disturbance during August, 2012 to October, 2012. The sub-committee may discuss. C.5 Any other item PRESENTATION ON SWITCHING OPERATION OF SHUNT REACTORS IN 400kV TRANSMISSION NETWORK BY POWERGRID. C.6 Date and Venue of next OCC It is proposed to hold the 7 th PCC meeting of NERPC on 15 th March, 2013 (Friday). As per roaster, Assam will be the host for 7 th PCC meeting. The exact venue will be intimated in due course. ***** 14